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Thread: Engine confusion...timing and other info

  1. #1
    ashhhhh Guest

    Engine confusion...timing and other info

    Hey all

    I have been trying to set the timing on my SIII with 2.25L Petrol and am getting quickly confused on a number of fronts...

    My engine number is 902695xxxxx, one manual I have says this is 8:1 and another 7:1....can anyone confirm which it is?

    I had also read previously that 1981 and onwards got the 5MB engine, my number goes against that apparently and the number range has been listed as 3MB on a couple of sites....so 3 or 5?

    Inside the engine bay there is a placard which states timing should be "6 degree ATDC, at 750-800rpm and with vac advance connected." (dynamic OR static)

    My engine has a single mark on the camshaft pulley and 4 pointer marks on a gauge attached to the block.
    The manual I have states that the right most pointer (when looking down on engine) is 6deg ATDC, next on left is TDC, then 3deg BTDC and finally 6deg BTDC.

    I have set the engine dynamically to 6deg ATDC and it certainly seems wrong, very slow at take off and down on power.

    Before I adjusted it the mark was way, way to the left of ANY of the pointers....yet it still seemed to run OK....

    Any advice much appreciated, I am getting pretty fed up with all this contradictory info!

    Cheers
    Ash

  2. #2
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    according to my workshop manuals

    any 901 engine is a is 8:1 and any 904 is 7:1

    the static timings for them is

    8:1 TDC on 90 octane and 3 degress ATDC for 85
    7:1 6 degrees BTDC for 90 octane 3 degress BTDC for 85 and TDC for 75 octane

    with todays unleaded (being 93 octane or better) you should be able to run with about 3 degrees BTDC static without any hassles. (every engine is a little different and usually a by ear tune will get you as far as 10 or 12 degrees before it knocks)

    the timing on the placard is for static or at idle with the vac advance disconnected.

    the dizzy if working properly on both engines advances

    9-11 degrees at 1000RPM
    14-16 degrees at 1600RPM
    and
    17-19 at 2000RPM

    the standard vac unit retards ignition
    0-.5 degrees at 1 in/Hg
    .5-3 degrees at 2 in/Hg
    2.5-3.5 at 3 in/Hg


    and according to the emission control section of the manual has you setting the timing to 6 degrees ATDC at 750-800 RPM but as near to but not over 800 RPM AFAIK only 8:1 engines have emission controls.
    Dave

    "In a Landrover the other vehicle is your crumple zone."

    For spelling call Rogets, for mechanicing call me.

    Fozzy, 2.25D SIII Ex DCA Ute
    Tdi autoManual d1 (gave it to the Mupion)
    Archaeoptersix 1990 6x6 dual cab(This things staying)


    If you've benefited from one or more of my posts please remember, your taxes paid for my skill sets, I'm just trying to make sure you get your monies worth.
    If you think you're in front on the deal, pay it forwards.

  3. #3
    JDNSW's Avatar
    JDNSW is offline RoverLord Silver Subscriber
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    Quote Originally Posted by ashhhhh View Post
    Hey all

    I have been trying to set the timing on my SIII with 2.25L Petrol and am getting quickly confused on a number of fronts...

    My engine number is 902695xxxxx, one manual I have says this is 8:1 and another 7:1....can anyone confirm which it is?

    I had also read previously that 1981 and onwards got the 5MB engine, my number goes against that apparently and the number range has been listed as 3MB on a couple of sites....so 3 or 5?
    ...........
    Cheers
    Ash
    If you check the head between the rocker cover and the carburetter, there should be a square boss cast on the top of the head between the two centre head bolts. This boss should have either 7 or 8 stamped on it. This is not absolutely reliable as the head may have been planed without the marking being altered. (Early heads, which should not be on your engine, but may have been fitted, do not have the boss, and there is not reliably enough metal to allow planing to 8:1)

    Although the literature suggests that the five bearing engine was fitted from 1981 on, it seems that Australian assembled vehicles never had five bearing engines. They were fitted to fully assembled vehicles imported to Australia, mainly station wagons. Consequently, they are quite rare in Australia. Note that the 2.25 engines, petrol or diesel were never sold in coil spring Landrovers in Australia - from the start of coil spring production until the Defender, only the V8 and the Isuzu were fitted to locally sold vehicles.

    For timing, follow Dave's instructions.

    John
    John

    JDNSW
    1986 110 County 3.9 diesel
    1970 2a 109 2.25 petrol

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